BRAINCAKEThe Photoelectric Effect Equation and Wave-Particle Duality
Einstein's photoelectric effect equation :hf = φ + KEmaxWhere φ is the work function of the metal. The work function is the minimum amount of energy needed to free the electron from the metal. Some electrons in the surface of the metal are closer to the positive metal ions than others. Their relative positions affect how much energy is needed to free them. Most electrons need a little above the threshold frequency to free them.A graph of KEmax against frequency is a straight line.the gradient is equal to the Planck constant, and the y intercept is - φ.Different metals have different work functions,So the threshold frequency of each metal is different.
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Key terms in this lesson
- energy
- The capacity of a system to do work.
- linear momentum
- The product of an object's mass and its velocity.
- wavelength
- The minimum distance between two points on a wave that are in phase, such as from one peak to the next.
- frequency
- The number of complete oscillations or wavelengths passing a given point per unit time.
- diffraction
- The spreading out of a wave as it passes through a gap or around an obstacle.
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